The present invention relates to an optical information reading apparatus having a function of optically reading an information code, such as one-dimensional code and a two-dimensional code, and also relates to its reading method.
The optical information reading apparatus units are recently used as an automatic information inputting and decoding apparatus in a wide variety of systems such as POS systems, OA systems and FA systems. One example of this kind of information code reading apparatus is a code reading apparatus disclosed in the Japanese Patent Application Laid-open No. 10-198754 (1998) applied for by the same applicant as that of this application.
This applicant, as disclosed in this patent document, uses an optical sensor, for example, having the resolution of 640 pixels×480 pixels (=307200 pixels) in total to pick up an image and decodes an information code contained in the picked-up image. According to this prior art, the time required for a bar code reading operation can be shortened.
In the field of optical information reading apparatuses, the requirement for high resolution is recently increasing to improve their reading performance. Accordingly, compared with a conventional type, the total pixel number of a new optical sensor used for picking up one image will need to be increased to a higher level (e.g. 802 pixels×602 pixels, 1077 pixels in lateral direction×788 pixels in vertical direction, approximately 400,000 pixels to 800,000 pixels or more). Accordingly, it will take a long time for accomplishing a reading operation and a decoding operation even if a conventional arrangement such as the one disclosed in the above prior art document is employed. When the reading and decoding time is long, a response time required for responding to a reading instruction will become long when a user issues such a reading instruction. The users will be dissatisfactory. Such a problem will also arise in a reading apparatus used for reading a bar code or other one-dimensional code. According to an arrangement of the present invention described in this application, it is possible to shorten the time required for reading and decoding operations even if an employed optical sensor has the resolution of 640 pixels×480 pixels (307200 pixels) in total.